If you’re like millions of people who are fighting the dreaded 3 p.m. slump, perhaps you’ve heard why taking a walk and stepping away from your desk or task can actually make you productive. The timing of when you choose to take this walk, however, makes all the difference.
A study published last month echoes what we already knew about taking walks to boost brain power: a 15-minute walk or a 10-minute run is an effective reset and refresh for a tired brain. It’s easy to fit in bite-sized breaks to stretch or get some fresh air but fitting in a solid chunk of time can be challenging for students and workers. Often, the only way to accomplish this is to incorporate it into a lunch break or save it for your afternoon break.
In winter, this timing may not matter so much; but in the warmer months, taking a 15-minute walk could actually give you the opposite effect! Researchers at the University of Tsukuba, Japan, found that walking on a hot summer’s day negatively impacted productivity and cognitive function. To illustrate, adult students took a test in an air-conditioned room for 30 minutes and were then divided into three groups. One group walked outside, the other sat outside and rested, and the last group stayed in the air-conditioning on a hot summer day.
After the 15 minutes was up, the students returned and were asked to take the same arithmetic test. The students who walked outside in the heat performed poorly, while the students who rested outside and those who stayed inside fared better and closer to their previous results. It wasn’t just being outside in the heat but walking in the heat that really affected mental performance.
This was also more noticeable in people who were already behind on sleep (notably in the male participants who slept less than 5 hours). The temperature was equal or greater to 44°C (112°F) which is classified under UTCI (Universal Thermal Climate Index) as very strong heat stress.
While the study is unclear if cognitive performance rebounded after resting in the air conditioning for a period of time before testing again, it can give us pause before we head outside on those extra-hot days when we’re already feeling sluggish.
Yuki Asano, Yusuke Nakamura, Asuka Suzuki-Parker, Shohei Aiba, Hiroyuki Kusaka. Effect of walking in heat-stressful outdoor environments in an urban setting on cognitive performance indoors. Building and Environment, 2022; 213: 108893 DOI: 10.1016/j.buildenv.2022.108893